Control device for fluid pressure plants



- Jan. 21, 1941. G. ALFIERI CONTROL DEVICE FOR FLUID PRESSURE ILANTS Filed Oct. 5, 1938 3 Sheets-Sheet 1 Jan. 21, 1941. ALF|ER| 2,229,162

CONTROL DEVICE FOR FLUID PRESSURE PLANTS Filed on. 5, 1958 s Sheets-Sheet 2 20 Z, 22 I6 I p Jan. 21, 1941. G. ALFlERl 2,229,162

CONTROL DEVICE FOR FLUID PRESSURE PLANTS Filed Oct. 5, 1938 3 Sheets-Sheet 3 i I I 5.9 44 I /0 37 I I/ l Patented Jan. 21, 1941 I UNITED srATr-zs 2.229.162 CONTROL navrcr: roa FLUID rnassrmn rmn'rs Giuseppe Alfieri, Milan,

brica Italiana Anonima, Milan,

Italy, assignor to Fab- Magneti Marelli Societi Italy, a corporation of Italy Application October 5, 1938, Serial No. 233,507

In Italy 8 Claim.

This invention relates to compressed air plants including a compressor and a reservoir fed by said compressor such as embodied in pressureair operated brakes for vehicles. and has for its object a control device which operates to efficiently connect the compressor with atmosphere when air pressure in said reservoir reaches a predetermined value the compressor then operating idly.

This invention also includes other features and advantages and means by which air may be obtained from said compressor under a pressure higher than the said predetermined pressure.

An embodiment of the present invention is shown by way of example on the annexed drawings and Fig. 1 is a transverse section of a device according to this invention on broken line I-I, Fig.

Fig. 2 is a section thereof on line 2-2, Fig. 4;

Fig. 3 is a section on line 3-3, Fig. 4;

Fig. 4 is a plan view with parts in section on line 4-4, Fig. 1. 1

The control device of this invention is intended to be afflxed on a compressed air reservoir shown diagrammatically by one of its walls by 62 and to control the communication of the outlet of an air compressor with said reservoir to supply compressed air therein until a predetermined pressure prevails therein and then to connect the compressor outlet with atmosphere to discharge the air fed by said compressor after the desiredpressure has been obtained in the cooperating reservoir; said device also provides means for drawing compressed air directly from said compressor at its full operative pressure when desired, as above stated.

The control device includes a casing I in which a cylinder 2 is provided and a piston 3 is mounted to reciprocate in said cylinder; 2. spring 4 has one end abutting on the cylinder bottom 21 and acts on said piston to restore it at the top end of cylinder 2.

The piston 3 loosely abuts on a stem 5 extend ing through an aperture of the cylinder bottom 21 and is pivotally connected at 12 with a twoarm lever I2, I2" fulcrumed at I3 on a depending extension 21' of said cylinder bottom 21,

A contact member 25 is provided on the top face of the piston 3 to cooperate with a contact 23 mounted on the cylinder head by means of insulating parts 24; the two contacts 25 and 23 are inserted in an electric circuit including a source of electric current and an indicator, not shown, to give an alarm at the time the air pres- October 13, 1937 sure in the reservoir is dropped to a low predetermined value.

A chamber 8 is provided in the casing I adjacent to the cylinder 2 and said chamber 8 is connected through an air filter hereinafter described with a duct 5| adapted to be connected with the output duct of a compressor, said connection being made through a path including the space 56, a perforated head 54, an air pervious layer 42, a perforated head 55 and the passage through II a hollow part 53.

A blow out port 9 leads from chamber 8'to atmosphere through a chamber 46 and ports 41 and is controlled by a ball valve I0 seated by a spring I I to close said port 9. 15

The casing I includes a further chamber I4 which is connected througha duct 44 (Fig. 3) with the compressed air reservoir 62: a further duct 45 leading from the chamber. I4 provides for connection with the system, as a brake plant, 2 to be supplied with compressed air under the control of the described device.

A passage 50 anda port Il further connect the chamber I4 with the space I8 intermediate the piston 3 and the top head of the cylinder 2. The chamber I4 is further connected with the chamber 8 through a port I5 under the control of a return ball valve I6; the valve I6 is normally held in its cutting off position when the compressor is inoperative by air pressure acting thereon from reservoir 62 through 44 and I4 and at the time the compressor is operative said valve I6 is removed from its seat by the air conveyed by the compressor to the chamber 8 this air then cooperating with the spring II to hold the blow out valve III on its seat.

A finger 32 fast on a plunger 3| mounted to slide in a bore 46 provided in a portion of the casing I'and extending in a direction parallel with the cylinder I is adapted to act on the valve 4 I II to open it, and said plunger 3I has a head 3I in front to the arm I2" of the lever I2, I2" which as above described is pivotally connected with the stem 5 of the piston 3. The plunger 3 I has outlet ports 41 and is biased to the illustrated position by a spring 31 operative on said plun|ger 3I and on a part stationary in the casing A groove 33 (Fig. 2) is provided in the side surface of the plunger 3I and is confined by bevel 5 surfaces as 33' and a roller 34 engages said groove; the roller 34 is carried by a plunger 35 mounted to reciprocate in a direction perpendicular to the axis of the plunger 3| in an extension I of the casing I and a spring 36 bearing on a ll plug 48 is operative on said plunger 35 to hold the roller 34 thereof engaged with the groove 33. An extending end 49' of a split resilient ring 49 embracing the extension I projects through an aperture of said extension I' and enters a slot 35' of the plunger 35 to prevent the plunger "and roller 34 thereof from rotating about the plunger axis. The finger 32 has such an extent as its tip is at a material distance from the valve III at the time the plunger 3| is in its position by which the roller 34 is engaged in the groove 33.

The duct 50 for connecting the chamber I4 with chamber I8 in the cylinder 2 is provided in a conical plug 38, angularly adjustable in a cooperating seat provided in the casing I and forced thereon by air pressure and by a spring 48; said plug 38 may be manipulated from outside for its angular adjustment by means of a handle not shown adapted to be engaged when required on a square end 4I thereof; the plug 38 may thus be shifted from the illustrated position in which the duct 50 thereof connects the cham ber I4 with port I1 and space I8 of the cylinder 2 into another position in which the interconnection of chamber I4 with space I8 is cutoff and said duct connects the chamber I4 directly with an air outlet 39 (Figs. 3 and 4) having means for connecting a delivery pipe, asa hose, thereto.

The device further includes a safety valve 30 (Fig. 4) having its seat provided in an outlet I3 from the chamber I4 and comprising a valve ball 28 loaded by a spring 2I which is adjustably supported by a plug 22; the flow from the chamber of valve 20 into the atmosphere occurs through The air filter located intermediate the chamber 8 and duct 5| connected with the air compressor consists of a layer 42 of air pervious material located intermediate two sleeves 52 and 53 and two perforated heads 54, 55; the whole is located in the central portion of a chamber 55 of the casing I and is held in position by a removable plug 51 and an intermediatespring 58.

A hood 43 having outlets 28 covers the device and is held in position by a handle nut 59 screwed on a bolt 68 extending from casing I.

In operation assuming the plug 38 in its position illustrated in Fig. 1 with its duct 58 connecting the casing chamber I4 with the space I8.

of the cylinder 2, the compressed air supplied from the compressor through the duct 5I enters the chamber 8 after having passed through the filtering material 42 said air flowing through duct 5 I, the space inside the sleeve 53, perforated head 55, air-pervious filtering material 42, perforated head 54 and the outer annular portion of the chamber 58 as shown by arrows.

Said air, while holding the valve I0 closed in cooperation with the spring II, removes the valve I6 from its seat and enters the chamber I4 to flow to ducts 44, 45 and hence to the reservoir 62. At the same time a portion of said air flows through the duct 58 and port II into the chamber I8 where it causes the piston 3 to move off from the cylinder head and holds it spaced from said head against the pressure of the spring 4, the lever I2, I2" being thus oscillated anticlockwise at an angle with respect to its position in Fig. 1.

On the air pressure increasing in the space I8 of the cylinder 2, after a certain displacement of the piston 3 and stem 5 corresponding with the distance intermediate the end of the arm I2 of the lever I2 and the head 3I of the plunger 3I, said piston 3 is restricted from further motion by the lever can" abutting on the plunger 3| v3 I which Iri'* turn is restricted from motion by the engagement ofthe roller 34 in the groove 33 thereof. A high pressure may thus build up in the space 8, I4, llbecause the blow out valve I8 is held seated. I

As soon as the overpressure thus building up inthe chamber llgoes .over a predetermined value, the a'ctionthe parts 3, 5, I2, I2 develop on the plunger 3.1 is suilicient to overcome the 'motioh restrictlng action of the roller 84 and spring 38. Then the plunger 3I by the action the tap ring bottom end surface 33' of its groove 33 exerts on the roller 34 and plunger 35 causes said rollern m recede and is driven to strike a violent impact on the w lve I8 under the action of the piston 3 whichsuddenly takes its position corresponding with the balance of actions of the high pressure operative in the chamber I8 and of the opposed pressure the spring 4 applies thereto. The above defined position is materially beyond the position in which the piston 3 Was restricted by the plunger 3| and cooperating Darts 34, 35, 38 the valve I8 beingthus'carricd positively by the impact applied thereto by the finger 32 into a position materially spaced from its seat. The momentum of the plunger 3|, 3| and finger 32' materially cooperates with the described actioninethat said parts engage the valve I8 after they have taken up a material speed.

In the above described conditions the action developed bytheapiston 3 on' the valve I0 cannot drop immediately by effect of the pressure fall in space :3, I4, 50,11, I8 occurringewhen the valve I8 begins to open as it would happen should the piston 3 act directly and gradually on the valve ID; on the contrary the valve I8 is carried into a fully open position by the described operation and a large connection of the inlet duct 5| through which compressed air is, supplied by the compressor is provided with the atmosphere through 5I, 53, 42, 58,8, 46, 41 while the valve I 8 closes under pressure from 82, 44, I4 to cut off the reservoir 82 from blow-out outlet 41. Accordingly the reservoir 62 is cut off from the compressor and no back pressure is operative on the compressor as soon as a predetermined rate of operative pressure obtains.

The described operation depends upon two factors, that is, on the overpressure which temporarily builds up in the chamber I8 and on the momentum the system 3I, 3I', 32 has at the time the engagement of roller 34 with the plunger 3| is removed and the piston 3 is abruptly released to move under the action of said overpressure.

On the pressure falling down in chamber I4 and consequently in chamber I8, the springs 4, 31 and II restore the piston 3, plunger 3I and valve I8- into their normal positions shown in Fig. 1; the plunger M is thus again engaged by the roller in the illustrated position, the blow out valve I8 is closed and the air supplied by the compressor may open the valve I6 and flow into the reservoir.

When the pressure within chamber I8 falls down to suchadegree as the piston 3 is carried by the spring 4 at the end of its stroke, the contacts 23 and 25 engage each other to close an alarm circuit as above described and give an indication as to the pressure within the reservoir having dropped under a predetermined value.

As above described the communication of the chamber 8 with .the port I! opening into the chamber I8 occurs through the duct 58 provided in the plug as which may be adjusted from out- I air supply outlet 3|, the control means 3, l, I, I2, 3|, I. are cut oil from their operation under the action of the compressed air and compressed air at the compressor delivery rate and pressure may be obtained from the outlet II, the path for said compressed air being as followszduct Ii, filter 42', chambers II, 8, l4, duct I. and outlet 3|.

Accordingly compressed air at a pressure independent of and over that adjusted for by the control device in the rvoir 02 may be derived directly from the evice; said over pressure air may be of advantage for. inflating the vehicle wheel pneumatic tires or for other purposes.

The communication of the supply duct It with either outlets 44, ll or ll always occurs through the fllter 42 and accordingly such foreign matters as may be conveyed by the air fed by the compressor may be prevented from reaching the means supplied with compressed air. The whole device has a comparatively small overall size and it may be afflxed directly on the cooperating reservoir 82; further the device is protected by the hood 0 which may be easily removed by the removal of the nut l8.

What I claim as my invention and desire to secure by United States Letters Patent is:

1. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir,

' a non-return check valve in said duct, a blowout valve in said duct ahead of said non-return valve, a part adapted to actuate said blow-out valve for opening it, said part having a side recess, a spring loaded member movable on a line transverse to the path of said part in its valveactuation motion, said member releasably engaging said part by entering said recess thereof, a cylinder connected with said reservoir, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and means imparting the action of said piston to said part for releasing it from said engaging member and subsequently driving said part against said blow-out valveto actuate said valve.

2. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir, a non-return check valve in said duct, a blow-out valve in said duct ahead of said non-return valve, a part adapted to actuate said blow-out valve for opening it said part having a side recess, a spring loaded member movable on a line transverse to the path of said part in its valve-actuation motion, said member releasably engaging said part by entering said recess thereof, said member withholding said part in a location at a distance from said blow-out valve, a cylinder connected with said reservoir, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder and means imparting the action of said piston to said part for I releasing it from said engaging member and subsequently driving said part against said blow-out valve to actuate said valve.

3. For a compressed 'fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir, a non-return check valve in said duct, a blow-out valve in said duct ahead of said non-return valve,

apartadaptedtoactuatesaidblow-outvalvesaid parthavin'gasiderecesa,aplungermovablecn a line transverse to the path ofsaidpart inits valve actuation motion, means on said plunger releasably n aging said part by entering said recessthereof, a spring forcing said plunger into position for engagement of said engagin means with-said'part. a springacting'on said part to.

restore it in its position with said recess engaged by said engaging means of said plunger, a cylinder connected with said reservoir, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and means imparting the action of said piston to said part for releasing it from said engaging means and subsequently driving said part against said blow-out valve to actuate said valve.

4. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir, a nonreturncheck valve in said duct, a blow out valve valve actuation motion, means on said plunger releasably engaging said (part by entering said recess thereof, a spring forcing said plunger into position for engagement of said engaging means with said part, a cylinder connected with said reservoir said cylinder extending along an axis substantially parallel to the path of said actuating part, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and a pivoted lever actuated by said piston and imparting its action to said part for releasing it from said engaging means and subsequently driving said part against said blow-out valve to actuate said valve.

5. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir, a non-return check valve in said duct, a blowout valve in said duct ahead of said non-return valve, a part adapted to actuate said blow-out valve said part having a side recess, a plunger movable on a line transverse to the path of said part in its valve actuation motion, means on said plunger releasably engaging said part by entering said recess thereof, a spring forcing said plunger into position for engagement of said engaging means with said part, a spring acting on said part to restore it in its position with said recess engaged by said engaging means of said plunger, a cylinder connected with said reservoir said cylinder extending along an axis substantially parallel to the path of said actuating part, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and a pivoted lever actuated by said piston and imparting its action to said part for releasing it from said engaging means and subsequently driving said part against said blowout valve to actuate said valve.

6. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a coma line transverse to the axis of said finger and part, meanson said plunger rcleasably engaging said part by entering said recess thereof, a spring forcing said plunger into position for ens sement of said engaging. means with said part, a spring acting on said part to restore it in its position with said recess engaged by engaging means of said plunger. a cylinder connected with said reservoir, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and means imparting the action of said piston to said part for releasing it from said engaging means and subsequently driving said finger against said blowout valve to actuate said valve.

'7. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir, a non-return check valve in said duct, a blowout valve in said duct ahead of said non-return valve, a flnger mounted in register with said blow-out valve, a part connected with said finger and having a side recess, a plunger movable on a line transverse to the axis of said finger and part, means on said plunger releasably engaging said part by entering said recess thereof said means withholding said flnger in a location at a distance from said blow-out valve, a spring forcing said plunger into position for engagement of said engaging means with said part, a spring acting on said part to restore it in its position with said recess engaged by said engaging means of said plunger, a cylinder connected with said reservoir, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and means imparting the action oi said piston to said part for releasing it from said engaging means and subsequently driving said flnger against said blow-out valve to actuate said valve.

I 8. For a compressed fluid plant including a fluid compressor and a compressed fluid reservoir, a pressure control device comprising a compressed fluid inlet duct leading to said reservoir,

a non-return check valve-in said duct, a blowout valve in said duct ahead of said non-retum valve, a finger mounted in register with said blow-out valve, a part connected with said finger and having a side recess, a plunger movable on a line transverse to the axis 01' said finger and part, means on said plunger releasably engaging said part by entering said recess thereof, a spring forcing said plunger into position for engagement of said engaging means with said part, a spring acting on said part to restore it in its position with said recess engaged by said engaging means of said plunger, a cylinder connected with said reservoir said cylinder extending along an axis substantially parallel to said finger, a return spring loaded piston operative in said cylinder under the fluid pressure in said reservoir and cylinder, and a. pivoted lever actuated by said piston and imparting its action to said part for releasing it from said engaging means and subsequently driving said finger against said blow-out valve to actuate said valve.

GIUSEPPE ALFIERI. 

